European patent application No. 0038756 to Deutsch and Glavan discloses cationic lipophilic complexes of technetium-99m that are useful as negative heart imaging agents in that they accumulate in the normal heart and visualize an infarct as a cold area on a relatively hot background of normal tissue.
The subject complexes of technetium-99m have lipophilic ligands and an overall cationic charge and are described by the formula EQU [(L).sub.2.sup.99m Tc(X).sub.2 ].sup..sym. X.sup..crclbar.,
wherein each L represents the same or different lipophilic ligand strongly chelating for a technetium-99m cation, and wherein the three X's are the same or different monovalent anionic ligand. Examples of such complexes include 99m-Tc(diars).sub.2 X.sub.2.sup.+ wherein diars is o--C.sub.6 H.sub.4 (As(CH.sub.3).sub.2).sub.2 (o-phenylenebis(dimethylarsine)) and X is Cl or Br, trans-99m-Tc(dmpe).sub.2 Cl.sub.2.sup.+ (wherein dmpe is (CH.sub.3).sub.2 P--CH.sub.2 CH.sub.2 --P(CH.sub.3).sub.2) which is said to be the preferred myocardial imaging agent and 99m-Tc(tetraphos)Cl.sub.2.sup.+ (wherein tetraphos is P(CH.sub.2 CH.sub.2 P(C.sub.6 H.sub.5).sub.2).sub.3). The technetium in these complexes is in an oxidation state of +3.
In two abstracts (J. Nucl. Med., 23(5): P16-P17 and Julich, Aug. 23-27, 1982, pgs 319-320), Jones et al disclose a class of technetium complexes containing various isonitrile ligands; the technetium in these complexes is in an oxidation state of +1. The compounds are useful as negative heart imaging agents.
Lock, in an abstract dealing with the chemistry of technetium (Julich, Aug. 23-27, 1982, pg 318) mentions technetium in the +1 oxidation state.